I've already added Android/Samsung MultiWindow mode, by adding some line inside the Manifest file. Unfortunately I can't find out how to add Floating/Popup mode to get something like this picture (note that the apps are floating).
(source: isource.com)
Somebody knows how to add the support for this view mode?
Make sure your manifest contains the following somewhere inside the application tag:
<meta-data
android:name="com.samsung.android.sdk.multiwindow.penwindow.enable"
android:value="true"/>
More info here